Ventilators have been utilized in foundations of building structures with louvers therein which may be opened or closed depending the ambient temperature. The basic ventilator structure includes a plurality of louvers and a hand operated element for closing the louvers during cold weather and opening same during warm weather. This foundation ventilator has an outer grill that is secured thereto to preclude ingress of insects or the like through the ventilator structure.
Substantial development effort has been directed to foundation type ventilators so as to improve same. In this regard, a number of patents have issued to various individuals as listed below directed to improved ventilator features:
U.S. Pat. No. 2,802,410--Robinson PA1 U.S. Pat. No. 3,202,082--Viehmann PA1 U.S. Pat. No. 3,220,079--Aggson PA1 U.S. Pat. No. 3,741,102--Kaiser PA1 U.S. Pat. No. 3,815,638--Martin PA1 U.S. Pat. No. 3,833,989--McCabe PA1 U.S. Pat. No. 3,864,889--Hobbs PA1 U.S. Pat. No. 302,215--Tucker PA1 U.S. Pat. No. 1,335,929--Allen PA1 U.S. Pat. No. 2,117,529--Wile et al PA1 U.S. Pat. No. 2,187,767--Akers PA1 U.S. Pat. No. 2,216,873--Browne PA1 U.S. Pat. No. 2,241,108--Akers PA1 U.S. Pat. No. 2,551,965--Petersen PA1 U.S. Pat. No. 2,814,977--Noll PA1 U.S. Pat. No. 3,195,441--Hedrick PA1 U.S. Pat. No. 3,027,090--Zerhan PA1 U.S. Pat. No. 3,068,776--Day PA1 U.S. Pat. No. 3,368,756--Edwards PA1 U.S. Pat. No. 3,436,016--Edwards PA1 U.S. Pat. No. 3,528,606--Witten
Likewise, development as proceeded along the lines of automatic opening and closing of the louvers of the ventilator assemblies as represented by the following listed patents:
None of the above cited prior art discloses or suggests the use of a ventilator assembly with the removable rear grill as defined by applicants herein. It is not believed that the prior art teaches or suggests applicants' claimed invention.
Removability of the rear grill is of substantial import to permit cleaning the ventilator assembly if and when desired, and though permanent installations of screens as shown in Witten, U.S. Pat. No. 3,528,606 for example have been used, they are not believed to be anticipatory or suggestive of applicants' concept.